gmail_read_attachment

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true and destructiveHint=false; the description adds valuable behavioral details beyond those: the 5 MiB read limit, base64 encoding, membership verification, and that no files are written or executed. It does not contradict the annotations, though it could clarify whether oversize attachments cause an error or truncated output.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two tight sentences with no filler; the most important operational constraints (size limit, base64, safety) are front-loaded and every clause adds meaning. This is appropriately concise for a straightforward read operation.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the lack of an output schema and the 0% parameter coverage, the description should explain more about the return value shape and how to select an attachment. It covers safety and size well, but leaves the agent without enough guidance on the exact parameters required to perform the read.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description must compensate, but it only says 'explicitly selected' and does not explain accountId, messageId, partId, or attachmentId. The required vs optional roles of these parameters remain unclear, especially how attachment selection actually maps to the available fields.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb ('Read'), resource ('message attachment'), and key constraints (5 MiB limit, base64 output). Clearly distinguishes from sibling tools like gmail_read_message and gmail_read_thread by targeting attachment content rather than message/thread content.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The phrase 'explicitly selected message attachment' implies the agent needs an attachment identifier and a parent message, but it never states when to prefer this tool over gmail_read_message or gmail_read_thread, nor does it mention prerequisites like first fetching attachment metadata. Usage context is implied rather than explicit.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.